Malayalam has three important regional dialects and a number of smaller ones. There is some difference in dialect along social, particularly caste, lines. As a result of these factors, the Malayalam language has developed diglossia, a distinction between the formal, literary language and colloquial forms of speech.

Malayalam evolved either from a western dialect of Tamil or from the branch of Proto-Dravidian from which modern Tamil also evolved. The earliest record of the language is an inscription dated to approximately 830 ce. An early and extensive influx of Sanskrit words influenced the Malayalam script. Known as Koleluttu (“Rod Script”), it is derived from the Grantha script, which in turn is derived from Brahmi. Koleluttu has letters to represent the entire corpus of sounds from both Dravidian and Sanskrit.

Like the Dravidian languages generally, Malayalam has a series of retroflex consonants (/ḍ/, /ṇ/, and /ṭ/) made by curling the tip of the tongue back to the roof of the mouth. It uses subject–object–verb word order and has a nominative-accusative case-marking pattern. Its pronominal system has “natural” gender, a form that marks the gender of humans masculine or feminine while designating all nonhuman nouns as neuter. Inflection is generally marked via suffixation. Unlike other Dravidian languages, Malayalam inflects its finite verb only for tense—not for person, number, or gender.

The earliest extant literary work in Malayalam is Ramacharitam, an epic poem written in the late 12th or early 13th century. In the subsequent centuries, besides a popular pattu (“song”) literature, there flourished a literature of mainly erotic poetry composed in the manipravalam (“ruby coral”) style, an admixture of Malayalam and Sanskrit.